Sexual and gender minority individuals (SGM) face discrimination, stigma, and health disparities. Advance Care Planning (ACP) aims to ensure people receive medical care that is consistent with their goals, preferences, and values as they become seriously ill. Our work in the parent R01 is to study the trends, barriers, and facilitators to the uptake of ACP and its impact on care. However, there exists scant research on ACP in the SGM community. This mixed- methods supplemental proposal will build on our existing research to better understand ACP among SGM adults and their caregivers. Aim 1: To understand factors associated with Advance Care Planning (ACP) discussions among transgender or gender non-binary Medicare beneficiaries using claims data. Using Fee-for-Service Medicare claims, we will utilize a previously validated diagnosis code algorithm designed to identify transgender or gender non-binary beneficiaries to measure the rate of billed ACP visits. We will examine uptake and use of this code during the years 2016- 2018, compared with other high needs populations. Aim 2: To understand the needs, lived experiences, and challenges facing self-identified sexual and gender minority (SGM) adults around ACP. Using a national polling survey, we will compare SGM adults with other respondents on a limited number of ACP issues, including experience appointing healthcare proxies, and completion of Advance Directives (ADs). A subset of SGM respondents will be re-contacted for follow-up semi-structured interviews for a more in-depth qualitative exploration of advance care planning with clinical providers and the role of family/partners/caregivers, legal next of kin status, and perceptions of bias and/or discrimination. Identifying patterns around ACP rates and engagement among SGM adults will help inform person-centered interventions to facilitate high quality ACP discussions among vulnerable or underserved populations. This project will address a critical evidence gap in conducting research to advance the science of caring for aging SGM adults.